When you indirectly tweet your feelings about someone to a friend who understands whats going on. The friend should be a good one, who you can "fake argue with" and no one will suspect a thing.

Annoying friend: Omg I hate my lyfe!!!!!~111!
You: @bestfriend I hate you you are so annoying!
Bestfriend: @You Please go die I really hate you
Annoying friend: Omg markers!!!!
You and best friend: The Classic Direct Indirect!

You and your best friend get your emotions out, and no one suspects a thing.